Image View size manipulation and conditional image loading with glide

MainActivity.kt

package me.anwarshahriar.bitmapwithglide

import android.content.Context
import android.graphics.BitmapFactory
import android.os.Bundle
import android.util.DisplayMetrics
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import androidx.appcompat.app.AppCompatActivity
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import com.bumptech.glide.Glide
import kotlinx.android.synthetic.main.activity_main.*

val data = Array(1000) { i ->
    when {
        i % 2 == 0 -> "test_image_1.jpg"
        i % 3 == 0 -> "test_image_2.jpg"
        i % 5 == 0 -> "test_image_3.png"
        i % 7 == 0 -> "test_image_4.png"
        else -> "test_image_5.gif"
    }
}

fun getDimens(context: Context, imageName: String): Pair<Int, Int> {
    val decodeOptions = BitmapFactory.Options().apply { inJustDecodeBounds = true }
    BitmapFactory.decodeStream(context.assets.open(imageName), null, decodeOptions)
    return Pair(decodeOptions.outWidth, decodeOptions.outHeight)
}

fun getImagePath(imageName: String) = "//android_asset/$imageName"

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val displayMetrics = DisplayMetrics()
        windowManager.defaultDisplay.getMetrics(displayMetrics)

        rvImages.setItemViewCacheSize(30)
        rvImages.layoutManager = LinearLayoutManager(this)
        val maxDimen = (displayMetrics.widthPixels * 0.6).toInt() // 60% of screen width
        rvImages.adapter = ImageAdapter(maxDimen, maxDimen, displayMetrics.density)
    }
}

class ImageAdapter(private val width: Int, private val height: Int, private val density: Float) :
    RecyclerView.Adapter<ImageViewHolder>() {


    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ImageViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.image_item, parent, false)
        return ImageViewHolder(view, maxWidth = width, maxHeight = height, density = density)
    }

    override fun getItemCount() = data.size

    override fun onBindViewHolder(holder: ImageViewHolder, position: Int) {
        holder.bind(data[position])
    }

}

class ImageViewHolder(itemView: View, val maxWidth: Int, val maxHeight: Int, val density: Float) :
    RecyclerView.ViewHolder(itemView) {

    private val ivWallpaper: ImageView = itemView.findViewById(R.id.ivWallpaper)
    private val layoutParams = ivWallpaper.layoutParams
    private val glideRequestManager = Glide.with(itemView)

    fun bind(imageName: String) {
        val (width, height) = getDimens(itemView.context, imageName)
        val scaleFactor = maxWidth / (width * 1f)
        if (width * density <= maxWidth && height * density <= maxHeight) {
            layoutParams.width = (width * density).toInt()
            layoutParams.height = (height * density).toInt()
            ivWallpaper.layoutParams = layoutParams
            glideRequestManager.asBitmap().load(getImagePath(imageName)).into(ivWallpaper)
        } else if (height * scaleFactor > maxHeight) {
            layoutParams.width = maxWidth
            layoutParams.height = maxHeight
            ivWallpaper.layoutParams = layoutParams
            glideRequestManager.asBitmap().load(getImagePath(imageName)).centerCrop().into(ivWallpaper)
        } else {
            layoutParams.width = maxWidth
            layoutParams.height = (height * scaleFactor).toInt()
            ivWallpaper.layoutParams = layoutParams
            glideRequestManager.asBitmap().load(getImagePath(imageName)).into(ivWallpaper)
        }
    }
}